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The ceiling serves as an ideal location for robots to handle transportation tasks, as it ensures minimal interference between automated guided vehicles (AGV) and human activities. A previous study developed a ceiling mobile robot called HanGrawler 2. It can travel at a high speed of 1.0 m/s to compete with ground vehicles. However, it occasionally fails during high-speed travel. This study aims to improve the reliability of starting, accelerating, and traveling at high speed. Optical motion capture is used to observe the crawler behavior of HanGrawler 2. The observation of the crawler behavior revealed that the crawler moves on an inflated trajectory during the high-speed movement. In addition, the experimental results show that the collision is not caused by the inflation, but by the push-in timing. The reliability of high-speed travel was improved by installing an encoder and optimizing the push-in timing in accordance with speed fluctuations. [ABSTRACT FROM AUTHOR]

The development of automated tractors is anticipated to address the problem of a declining and aging agricultural labor force. However, there are numerous situations in which automatic driving is difficult in the field. We developed a remote operation system allowing novice tractor drivers to control a tractor remotely in situations where automatic driving is difficult and evaluated its performance on a real tractor in a field. Our challenge was to design a user interface (UI) that allows novices to comprehend the tractor's status and return the tractor situation where automatic operation is possible. The system's UI is inspired by popular video games. In experiments, even novice tractor drivers with little or no experience driving automobiles or playing video games could remotely control the tractor and till according to the goal line. In addition, the participants dealt with an invisible obstacle by viewing illustrations of the tractor sensor data. The designed UI's operation methods and operator attributes were analyzed. Through the experiment, the following facts were revealed. A method of operation that allows the analog stick to adhere to the mechanical guide results in smooth operation. In addition, the participant's preferred control method depends on his/her gaming experience. Thus, this study clarifies some of the specifications and design guidelines necessary for a novice‐friendly remote UI for the remote operation of a tractor. [ABSTRACT FROM AUTHOR]

Our research group has been developing an automated modularized rail structure construction system. Our system provides robot's locomotion and operational infrastructure in hazardous environments where manned work is difficult. In previous studies, various modules and robots have been developed, and stable transfer of modules between robots in multiple postures has been achieved. However, 3-D construction is not yet realized. In this study, the relationship between the contact force and posture of the constructor robot's (C-robot) end-effector is estimated through force balance calculation and deformation analysis is performed based on the finite element method. The results of construction experiment showed that pushing motion and improvement of the stiffness of the C-robot's grasping part increase the success rate of module construction in the vertically downward direction, which is the most difficult condition. Finally, this study proved that 3-D construction of a modularized rail structure is feasible in various posture condition. [ABSTRACT FROM AUTHOR]

In recent times, research on highly efficient construction has gained increasing popularity. During construction with hydraulic excavators, the sequence of excavation motions significantly affects the duration and precision of the work; therefore, it should be as efficient as possible. Because automation is still difficult, the ability improvement support system of nonskilled operators is required. However, currently, there exists no effective method for evaluating or planning the excavation motion sequence. This study proposes a method for evaluating excavation motion sequences based on a pattern recognition technique. First, the data array of hydraulic excavator motions is divided into unit excavation motions, characterized using a clustering method. Second, the patterns are divided into excavation phases with similar excavation motion patterns. Finally, the excavation motion sequence is evaluated by calculating the transition frequency between excavation phases. The result shows that the proposed approach can classify the skill level of the operator with accuracy of 0.8. Therefore, the frequency of excavation phase transitions can be used as a useful indicator for evaluating excavation motion sequences. [ABSTRACT FROM AUTHOR]

In the present paper, we describe a method for constructing a remote ultrasound diagnostic system. Remote diagnosis can be realized using a communication network. We have developed a master--slave type remote medical system to diagnose shoulder diseases, such as dialysis-related amyloid arthropathy (DRAA), by ultrasonographic images. Proper positioning, orientation, and contact force between the ultrasound probe and the affected area of the patient are required in order to acquire proper diagnostic images. Safety and manipulability are also required when operating the remote medical system through a communication network. Therefore, the system has impedance control capability for positioning of the master and slave manipulators in order to convey the contact force and enhance manipulability. In addition, the system has continuous-path control capability for the orientation of the slave manipulator in order to realize smooth and accurate motion of the ultrasound probe, even if the sampling rate of the transmission of the orientation data of the master manipulator is not sufficient. The results of remote diagnostic experiments demonstrated that a healthcare professional could diagnose real patients through a communication network using the constructed system. Index Terms--Continuous-path control, impedance control, master--slave manipulation, remote medical system, remote ultrasound diagnostic system.

Nanomechanical resonators can detect various small physical quantities. It is necessary to increase the sensitivity of nanomechanical resonators. In this study, a deep learning-based method is developed for sensitive detection of vibration states of nanomechanical resonators. It enables one to explore the most highly sensitive vibration states without missing targets while conventional methods focus only on the resonant frequency. The proposed method was evaluated with laser intensity. Sensitive measurement of laser intensity has the potential for applications in laser wavelength measurement. The proposed method could identify laser intensity at intervals of 0.03 mW at which the resonance frequency did not shift. Grad-CAM was used to clarify features on the vibration spectra used in the convolutional neural network. Frequency bands other than the resonance frequency band were used for the laser intensity measurement. This result implies that there is a possibility that highly sensitive vibration behavior exists outside the resonance frequency. [ABSTRACT FROM AUTHOR]

Background: Based on the assumption that systemic metabolic disorders affect cognitive function, we have developed a deep neural network (DNN) model that can estimate cognitive function based on basic blood test data that do not contain dementia-specific biomarkers. In this study, we used the same DNN model to assess whether basic blood data can be used to estimate cerebral atrophy. Methods: We used data from 1,310 subjects (58.32 ± 12.91years old) enrolled in the Brain Doc Bank. The average Mini Mental State Examination score was 28.6 ± 1.9. The degree of cerebral atrophy was determined using the MRI-based index (GM-BHQ). First, we evaluated the correlations between the subjects' age, blood data, and GM-BHQ. Next, we developed DNN models to assess the GM-BHQ: one used subjects' age and blood data, while the other used only blood data for input items. Results: There was a negative correlation between age and GM-BHQ scores (r = -0.71). The subjects' age was positively correlated with blood urea nitrogen (BUN) (r = 0.40), alkaline phosphatase (ALP) (r = 0.22), glucose (GLU) (r = 0.22), and negative correlations with red blood cell counts (RBC) (r = −0.29) and platelet counts (PLT) (r = −0.26). GM-BHQ correlated with BUN (r = −0.30), GLU (r = −0.26), PLT (r = 0.26), and ALP (r = 0.22). The GM-BHQ estimated by the DNN model with subject age exhibited a positive correlation with the ground truth GM-BHQ (r = 0.70). Furthermore, even if the DNN model without subject age was used, the estimated GM-BHQ showed a significant positive correlation with ground truth GM-BHQ (r = 0.58). Age was the most important variable for estimating GM-BHQ. Discussion: Aging had the greatest effect on cerebral atrophy. Aging also affects various organs, such as the kidney, and causes changes in systemic metabolic status, which may contribute to cerebral atrophy and cognitive impairment. The DNN model may serve as a new screening test for dementia using basic blood tests for health examinations. Finally, the blood data reflect systemic metabolic disorders in each subject—this method may thus contribute to personalized care. [ABSTRACT FROM AUTHOR]

At urban production sites, laser cutting is an essential technology for high-speed flexible sheet-metal processing. This study aims to detect defective cuts by sensing laser-cutting-induced light emission and elucidate meaningful features for processing-based detection. The proposed method comprises three steps. In the first step, the sensors installed in the laser head acquire the spectra of light generated during processing, and data analysis software converts the spectral data into spectrograms and stacked-graph images. In the second step, image processing software extracts the edges of both images and emphasizes the periodic features in normal laser cutting. In the final step, a one-class support vector machine recognizes defective cuts from the extracted features. Verification tests using multiple normal and abnormal cut data confirmed that the proposed method accurately detected defective cuts. [ABSTRACT FROM AUTHOR]

When stress and strain induced in a nanomechanical resonator are measured by micro-Raman spectroscopy, the analysis depth is longer than the thickness of the resonator. In cases where the resonator has stress depth distribution, the observed spectrum reflects the stress conditions at each depth and the shape of the spectrum deforms. We have developed a model of Raman spectrum formation and a method to quantify the stress depth distribution. The proposed model is expressed as a sum of several Voigt functions with individual intensities that depend on each depth and absorption characteristic, and the proposed quantification method applies nonlinear multiple regression analysis by using the model. We used this model to measure the Raman spectrum of a bent cantilever and calculate the stress depth distribution. We found that our model could obtain comparable results to those obtained by the finite element method. [ABSTRACT FROM AUTHOR]

A tungsten-carbide (W-C) superconductor/normal metal/superconductor (SNS) Josephson junction has been fabricated using focused-ion-beam chemical vapour deposition (FIB-CVD). Under certain process conditions, the component ratio has been tuned from W: C: Ga = 26%: 66%: 8% in the superconducting wires to W: C: Ga = 14%: 79%: 7% in the metallic junction. The critical current density at 2.5�K in the SNS Josephson junction is 1/3 of that in W-C superconducting nanowire. Also, a Fraunhofer-like oscillation of critical current in the junction with four periods is observed. FIB-CVD opens avenues for novel functional superconducting nanodevices. [ABSTRACT FROM AUTHOR]

Free-space-nanowiring using focused-ion-beam chemical vapor deposition (FIB-CVD) has been demonstrated to enable the fabrication of various innovative three-dimensional (3D) nanodevices with overhanging structures. However, due to the change in growth characteristics, it is difficult to fabricate a free-space-nanostructure larger than several micrometers while keeping a uniform angle. Normally, the free-space-nanowire deviates downward from the starting angle after becoming approximately 2 μm long. In this study, the authors proposed a technology to fabricate ultralong horizontal free-space-nanowire by using the growth angle dependency of specimen current and carrying out feedback control of the scanning speed on Ga+ FIB. The feedback control system monitors the specimen current and controls the scanning speed of FIB in real-time while judging the value of specimen current. Ultralong horizontal free-space-nanowire with a length more than 30 μm and a length to thickness ratio as high as 300 was achieved. The results verified that real-time feedback control on FIB-CVD is a promising technology for the fabrication of large scale free-space-nanostructure and that a larger variety of 3D nanodevices can be achieved by applying this technology to the computer pattern generator. [ABSTRACT FROM AUTHOR]

The authors fabricated a resonant frequency-tunable diamondlike carbon (DLC) resonator by focused-ion-beam chemical vapor deposition and a wet-etching process for fabrication of a functional resonant device. The resonant frequency of the DLC resonator with a cantilever shape was controlled electrically via the electrostatic attractive force generated by the opposite electrode. As a result, we achieved an extremely large resonant frequency tuning ratio of approximately 730%. This indicates that the electrostatic attractive force, when added to the restorative force of the DLC resonator, works effectively to change the resonant frequency. [ABSTRACT FROM AUTHOR]

A simple method of applying tensile stress to nanomechanical resonators was proposed and demonstrated. Two parallel beams were fabricated by wet etching. The beams then stuck to each other due to surface tension caused by the rinse solution and formed a stiction resonator. The stuck beams were stressed because of the deformation caused by the sticking. The stiction resonators were modeled to estimate the sticking length and evaluate the strain of the resonators. The maximum resonator strain obtained in this study was over 0.3%. The quality factors of the stiction resonators were then experimentally evaluated. Results showed that tensile stress had a significant effect on the quality factor enhancement. Using stiction is an effective, useful, and widely applicable method for the tensile stress application. [ABSTRACT FROM AUTHOR]

An ultra-thin carbon nanomechanical resonator was fabricated from poly(methyl methacrylate) (PMMA) using focused-ion-beam (FIB) and electron-beam dual-beam lithography. A suspended PMMA structure was cured using an ion-beam modification technique using a 30-kV Ga+ FIB, and carbonized to a diamondlike carbon. In addition, we analyzed the vibrational properties of the cured PMMA nanowire to confirm that it functioned as a resonant structure. [ABSTRACT FROM AUTHOR]

Hopping growth characteristics were examined to clarify the growth mechanism of three-dimensional nanostructures fabricated using focused-ion-beam chemical-vapor deposition (FIB-CVD). In this study, the gas density distribution of FIB-CVD was examined. As a result, a gas density has a large distribution on the vertical direction. However, the growth mechanism of a hopping nanostructure could not be explained completely. Therefore, sequential scanning ion microscope images of a hopping growth process were captured. It was found that the gap distance between the growth edges of the upper and lower structures changed during the hopping structure growth. This indicated the positional relationship between the Ga+ FIB and the growth structure. The change in this relationship induced the formation of a bridge bent structure and the change in the growth direction of the upper structure. To confirm the cause of the lower structure growth, the relationship between the Ga+ penetration depth into diamondlike carbon and the thickness of the upper structure was examined. The deposition onto the substrate was caused by the Ga+ FIB’s tail (directly irradiated beam). A hopping growth structure was formed by the repetition of these growth processes. [ABSTRACT FROM AUTHOR]

We developed a robot-assisted fracture reduction system (FRAC-Robo) to assist anatomical reduction and to maintain reduction during internal fixation while recording the procedure in a log. We conducted two experiments before using FRAC-Robo clinically. In the first experiment using the FRAC-Robo system, we measured the maximum force and torque required to pull and rotate the limbs of healthy conscious volunteers until they felt pain or abnormality. The average maximum traction force applied to the lower limb was 250.7 N, and the average maximum torque was 5.6 Nm in internal rotation and 7.6 Nm in external rotation for 30° of abduction of hip. In the second experiment, we measured the traction force and rotation torque during the reduction of proximal femoral fractures. The average traction force and rotation torque needed for reduction were 215.9 N and 3.2 Nm, respectively. On the basis of these results, we consider that FRAC-Robo can generate sufficient force and torque to reduce femoral fractures safely. [ABSTRACT FROM AUTHOR]

Tungsten-carbide (W-C) nanowires have been deposited by focused-ion-beam chemical vapor deposition (FIB-CVD). Mixtures of C14H10 and W(CO)6 are used as precursors. For certain precursor ratios, our nanowires become superconducting with a Tc as high as 5.8 K. Also, freestanding W-C nano pillars were grown by FIB-CVD. The growth rate of the deposition from the mixture is at most 4.25 times higher than W(CO)6 is used as the precursor. This growth rate greatly facilitates the fabrication of three-dimensional superconducting structures. [ABSTRACT FROM AUTHOR]

We used SU-8 shrinkage to fabricate strained graphene resonators to produce a high quality factor in a graphene resonator. A-few-layer graphene resonators were fabricated on a trench of an SU-8 resist. These resonators were clamped with diamond-like carbon (DLC), which was deposited by using focused-ion-beam chemical vapor deposition (FIB-CVD), and trimmed by using FIB etching. Annealing was used to apply tensile strain to the graphene resonators because SU-8 shrinks drastically. We also observed an increase in resonant frequency and quality factor in these graphene resonators after annealing. At room temperature, the quality factor of the best sample exceeded 7,000 for a resonator length of 10 µm. [ABSTRACT FROM AUTHOR]

Focused-ion-beam chemical vapor deposition (FIB-CVD) is a key technology to achieve the arbitrary three-dimensional (3D) nano- and microstructure fabrication. However, most of 3D nanostructure fabrications have focused on upward or lateral growth whereas few of them focused on downward growth. The downward growth characteristics of air nanowires were investigated in order to achieve the fabrication of more arbitrary 3D nanostructures. As a result, it was not able to fabricate a 1 µm long downward growth nanowire with an angle lower than -10°. Also, we found that a nanowire with an angle lower than -18° cannot be fabricated. Furthermore, we demonstrated the fabrication of 3D nanostructure including downward growth by changing the scan speeds of Ga+ FIB during fabrication. With controlling the downward growth, the fabrication of more various 3D nanostructures can be achieved. [ABSTRACT FROM AUTHOR]

In this study, the electrical material characteristics of a three-dimensional (3D) diamondlike carbon (DLC) structure fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD) were evaluated to realize functional 3D nano- and micromechanical devices based on the piezoresistive material. However, the DLC cantilever structure fabricated by FIB-CVD did not exhibit piezoresistive properties due to the incorporated gallium (Ga), which was implanted by Ga+ FIB irradiation. Therefore, a method for the modification of material characteristics was examined to introduce piezoresistive properties in the 3D DLC structure fabricated by FIB-CVD. Long-time annealing (12 h or more) at a low temperature (300 °C) was found to be an effective method to realize a 3D DLC structure with piezoresistive properties. Long-time annealing at low temperatures caused Ga elimination from the DLC without any change in the sp2/(sp2+sp3) ratio. The values of the gauge factor were in the range of 2-34. 3D nano- and microstructures with piezoresistive properties could be realized by FIB-CVD and annealing treatment. [ABSTRACT FROM AUTHOR]

Mechanical resonators are applicable to sensors owing to their vibration characteristics. When a mechanical resonator is used as a sensor, the Q factor of resonance is a very important characteristic for achieving a high sensitivity of the resonator. Several trials have been reported to improve the Q factor by surface treatment. However, how the physical or chemical state of the resonator surface affects the Q factor has not yet been clarified. In this study, we examined the effect of the surface state on the Q factor. From experiments for examining surface-treated samples, we found that the Q factor increases with reactive ion etching (RIE) with CF4 gas, and decreases with Ar or O2 gas. To evaluate the effect of the surface state on the Q factor, the surface free energy and chemical bond state changes of the resonator surface were measured. From the result of the experiments, it was proved that lower surface free energies result in larger Q factors. [ABSTRACT FROM AUTHOR]

Nano- and microstructures fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD) have a core–shell structure caused by the scattering profiles of Ga ions and secondary electrons (SEs). This structural characteristic makes it difficult to design functions of nano-electromechanical devices. Therefore, non-core–shell structure deposition by the control of SE emission was examined to facilitate the function design of nanoelectromechanical devices. Non-core–shell structure deposition was achieved by applying voltage during carbon nanostructure growth. We also evaluated the growth characteristics of non-core–shell structure deposition. We found that the growth rate of a nanostructure did not change when voltage was applied. Furthermore, we evaluated the mechanical material characteristics (density and Young's modulus) of a non-core–shell structure by measuring of the resonant frequency shift of a Si cantilever using the electron beam method. We found that the non-core–shell structure had a high density (6.5 g/cm3) and a high Young's modulus (800 GPa). These results indicate that the technique for non-core–shell structure deposition is useful in achieving nanoelectromechanical devices. [ABSTRACT FROM AUTHOR]

In this study, we used a transmission electron microscope (TEM) to evaluate the structure of the gallium (Ga) sphere formed on the tip of a diamond-like carbon (DLC) pillar fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD). Until now, details of the phenomenon induced by Ga eduction were remained unclear. We found that a graphite shell was formed on the surface of the Ga sphere after annealing. In addition, we demonstrated that this graphite shell film could be separated from the Ga sphere by performing a second annealing treatment. In-situ observations of the formation of the graphite shell film were carried out using TEM to clarify the process by which it was separated from the Ga sphere. The thermal expansion of Ga led to the separation of the graphite shell film, and Ga was vaporized from within the Ga sphere. These results imply that Ga is able to catalyze for the graphitization of carbon. The development of carbon nanodevices can be expected by using this novel phenomenon induced by Ga. [ABSTRACT FROM AUTHOR]

A method for evaluating the dynamic characteristics of micro- and nanoresonators with high spatial resolution is proposed. The mechanical resonance of circular micromembrane resonators is directly induced by voltage applied from the microprobe of a scanning probe microscopy (SPM) system. The vibration amplitude is simultaneously detected as height information by SPM. Experimentally, the resonant properties of fundamental and higher-order modes of 200-nm-thick GaAs micromembranes were measured. The frequency of the highest mode is 3.4 MHz and its resonant amplitude is about 1 nm. The resonant amplitude increases with increasing actuation voltage in a linear manner at voltages below 180 mV. Large actuation voltage induces nonlinear vibration with the spring soften effect, which originates from the strong attractive force induced by the electronic field between the probe and membrane. The high tapping force, which is repulsive, induces another type of nonlinear vibration caused by the spring harden effect. The simultaneous actuation and detection for mechanical resonators based on SPM technology reveals the characteristics of the mechanical interaction force between the micromembrane and microprobe. [ABSTRACT FROM AUTHOR]

We describe a method for evaluating thermal–mechanical vibration amplitude by means of analysis of scanning electron microscopy images. The samples used were carbon nanopillars of different heights grown by focused-ion-beam-induced chemical vapor deposition. The secondary electron yield profile of carbon nanopillars excited by thermal noise is modeled, and vibration amplitude is determined by fitting the modeled profile to the experimental profile. The Young's modulus of carbon nanopillars is deduced from the determined amplitude. Furthermore, the density of carbon nanopillars is estimated from the deduced Young's modulus and the measured resonant frequency. The obtained Young's moduli and densities range from 51 to 78 GPa and from 2500 to 3500 kg/m3, respectively. [ABSTRACT FROM AUTHOR]

An application of electron beams was examined to evaluate vibrational characteristics. The relationship between the secondary electron intensities and the amplitude of mechanical resonators has been unclear. In this study, the relationship was investigated to evaluate the amplitude and the quality factor using the electron beam method. An expression to estimate the amplitude from the signal intensity was developed by modeling the secondary electron signal as a pulse wave. Conversion of the signal intensities to amplitudes enabled us to evaluate the quality factor. Then, experiments comparing the amplitude of a microcantilever estimated using the electron beam method to that directly measured from the scanning electron microscope image were conducted. The estimated and directly measured amplitudes agreed well, and the quality factors evaluated from both amplitudes also agreed well. Thus, we conclude that the electron beam method can reliably evaluate the quality factor of mechanical resonators. [ABSTRACT FROM AUTHOR]

We investigated the height dependence of the Young's modulus for carbon nanopillars grown by focused-ion-beam-induced chemical vapor deposition (FIB-CVD) using phenanthrene gas as a source material. Carbon nanopillars of different heights were grown by FIB-CVD at various growth times and a fixed ion-beam focal point. The growth heights ranged from 3.6 to 35.6 µm. The diameters at the bottoms of the pillars were nearly the same, 100 nm, and it increased as the growth progressed. Young's modulus of the carbon nanopillars was evaluated from resonant frequency for mechanical vibration using uniform and nonuniform models. Young's moduli differed for different growth heights for both of the models. [ABSTRACT FROM AUTHOR]